Actuatable vehicle occupant protection systems are known in the art. Such protection systems may include one or more vehicle crash sensors for detecting the occurrence of a vehicle crash condition. When a vehicle crash condition is detected by the crash sensor, the protection system may actuate an inflatable device, such as an air bag, for helping to protect an occupant of the vehicle.
Certain types of vehicle crash sensors may include mechanical devices, such as switches, that close in response to deformation of the vehicle or a sudden deceleration of the vehicle. The closure of the mechanical device indicates the occurrence of a vehicle crash condition. Other vehicle crash sensors may include electrical devices, such as an accelerometer, for detection of a crash condition. When a processed output of the electrical crash sensor device, for example, a voltage level crosses a threshold value, a vehicle crash condition is determined to be occurring, and the actuatable restraining device is actuated.
Vehicle crash sensors for detecting a side impact to a vehicle must have particularly rapid response times as the time period for actuating an inflatable device for occupant protection during a side impact event is significantly less than the time period needed for actuating an inflatable device for occupant protection during a frontal impact event. To help improve the response time of a vehicle crash sensor for sensing side impacts, it is common to locate the vehicle crash sensor at a side location of the vehicle, such as within a side door of the vehicle. Such side impact crash sensor arrangements may include accelerometers and/or pressure sensors that respectively monitor for changes in the vehicle's sideways acceleration and changes in pressure within a vehicle door as would occur upon crushing of the vehicle door. The vehicle side crash event may be determined in response to both the side acceleration and pressure change signals.